JPS6411779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a temperature control circuit for a feed water heater in a sanitary washing device.

[Conventional technology]

In sanitary cleaning equipment, the temperature of the hot water discharged from the hot water tank of the water heater is required to be maintained at a predetermined temperature that people feel is appropriate because the hot water comes into direct contact with sensitive parts of the body. .

Typical hot water temperature control involves detecting the temperature in a hot water storage tank so that the temperature of the hot water that is discharged remains constant. However, the temperature distribution of the hot water in the hot water storage tank is uneven. For example, the temperature near the water inlet is low, and the temperature near the outlet is at the set temperature. In this regard, conventional temperature control is performed by detecting the temperature at only one point in the hot water storage tank, and takes into account the temperature of the water supplied to the tank, the amount of water discharged, the temperature distribution inside the tank, etc. It wasn't paid.

Therefore, the applicant of this patent has developed the following sanitary cleaning device.

In the sanitary cleaning device, the water supplied into the tank of the hot water storage tank pushes up the hot water stored in the tank, and the hot water is discharged from the outlet at the top of the hot water storage tank.
The water inlet is located at the bottom of the tank. Furthermore, a heater is also placed at the bottom of the tank in order to efficiently heat the water supplied into the tank. Two temperature sensors are installed inside the hot water tank. this house,
One is a first temperature sensor provided near the water inlet at the bottom of the hot water storage tank, and the other is a second temperature sensor provided near the hot water outlet at the top of the hot water storage tank. These two temperature sensors constitute a temperature detection section, and the temperature of the hot water is controlled by the temperature control circuit section based on the temperature detected by these two temperature sensors.

Here, the first temperature sensor detects the temperature of water supplied from the water inlet, sends the detected value to the temperature control circuit section, and promptly energizes the heating section, thereby reducing the temperature of the lower part of the tank due to water supply. Prevents water temperature from dropping. Further, the first temperature sensor functions to always maintain the water temperature in the tank at a predetermined temperature even during discharging water. On the other hand, the second temperature sensor functions to detect the approximately average temperature within the tank and maintain the water temperature within the tank at a predetermined temperature.

By controlling the hot water based on the detected value by the temperature sensor installed in this way, it is possible to always discharge water at a set temperature even during continuous washing for a long time. In addition, by pushing up the hot water in the tank and providing an appropriate volume to the hot water storage tank, during normal usage hours, the temperature can be controlled using only the second temperature sensor that detects the approximate average temperature inside the tank. It also has the ability to maintain a predetermined warm temperature even when configured with a circuit.

[Problem that the invention seeks to solve]

Abnormal rises in water temperature in the event of a temperature sensor failure are generally avoided by a fail-safe method in which all functions of the feed water heating section are stopped. However, this method of stopping all functions of the feed water heating section has little practical effect.

Therefore, even if one of the temperature sensors fails, if the function of the water supply heating section can be maintained during normal usage hours, the practical effect will be greater.

That is, the present invention is based on the premise that the temperature of hot water is controlled using the two temperature sensors in normal times, and that water is always spouted at a predetermined temperature during continuous washing for a long time. It is an object of the present invention to at least compensate the conventional temperature control operation by the output of the second temperature sensor when the first temperature sensor fails.

[Means and actions for solving problems]

In order to achieve this object, the present invention provides a first temperature sensor disposed near the water inlet at the bottom of the hot water storage tank, a second temperature sensor disposed near the hot water outlet at the top of the hot water storage tank, and A temperature control command corresponding to the temperature of water entering the hot water storage tank detected by the first temperature sensor is given to the heating section provided in the hot water storage tank, and a temperature control command corresponding to the temperature of water entering the hot water storage tank detected by the second temperature sensor is applied. In a sanitary cleaning device comprising a temperature control section that gives a temperature control command to the heating section according to a substantially average temperature,
Means for detecting a failure in the open state of the first temperature sensor and the second temperature sensor is provided, and when the first temperature sensor fails, the second temperature sensor
The temperature control section is characterized in that the temperature control section is provided with means for controlling the temperature of the heating section based on the output of the second temperature sensor, and for stopping power supply to the heating section when the second temperature sensor fails.

As a result, if the first temperature sensor that detects the temperature of water supplied from the water inlet fails, only the second temperature sensor that detects the approximate average temperature inside the tank has the ability to maintain a predetermined temperature. . On the other hand, the second
If the first temperature sensor fails, the first temperature sensor will not be able to detect the approximate average temperature, and there is a risk that the temperature of the hot water will exceed the set temperature, so the function of the feed water heater is stopped. the result,
The practical effect as a sanitary cleaning device is greatly improved.

〔Example〕

Below, features of the present invention will be specifically explained based on embodiments shown in the drawings.

The figure shows an example of the temperature control circuit of this embodiment.

The first temperature sensor and the second temperature sensor are configured by a negative characteristic thermistor 1 and a negative characteristic thermistor 21, respectively. Furthermore, a heater 27 is used as the heating section.

Negative characteristic thermistor 1 as a first temperature sensor
A change in the temperature of the hot water near the heat-sensitive part of is replaced by a change in the resistance value of the negative characteristic thermistor 1. This change in resistance value changes the DC voltage between the terminals in the figure by the resistance value of negative characteristic thermistor 1 and resistor 2.
and the sum of the resistance values of the variable resistor 3 for setting the control temperature, and the voltage value is divided by the resistance ratio and converted into an electrical signal. This is the potential at point (a) in the figure. This electrical signal is used for voltage comparison, which is the first temperature comparator.
The voltage is input to the negative input terminal of the IC 6 and the positive input terminal of the voltage comparison IC 9, which is the first failure detector.

The + side input terminal of the voltage comparison IC 6 receives the DC voltage applied between the terminal and the resistor 4.
The voltage is divided by the resistance ratio between the voltage and the resistor 5, and the potential at point (b) is obtained. Then, the potential at the point (b) is used for voltage comparison.
It is set as the reference potential of IC6.

Resistor 7 is set when the output terminal of voltage comparison IC 6 is ON.
- It has the effect of changing the potential at point (b), which is the reference potential, in response to being turned off, and giving hysteresis to the operation of the voltage comparison IC 6. Also, resistor 8
is a resistor for stabilizing the output potential from the output terminals of the voltage comparison IC 6 and the voltage comparison IC 9.

For voltage comparison to act as a second fault detector
The negative input terminal of the IC 12 and the negative input terminal of the voltage comparison IC 15 which acts as a second temperature comparator are connected to the temperature change of hot water near the heat sensitive part of the negative characteristic thermistor 21 which acts as a second temperature sensor. A signal that is converted into an electrical signal by replacing it with a change in the resistance value of the negative characteristic thermistor 21 is commonly input.
The potential as an electrical signal of the negative characteristic thermistor 21 is obtained by dividing the DC voltage applied between the terminals by the resistance value of the negative characteristic thermistor 21, the resistance ratio of the resistor 22, and the control temperature setting variable resistor 23. and the potential is taken as the potential at point (H).

The negative input terminal of the voltage comparison IC 9 and the positive input terminal of the voltage comparison IC 12 are input terminals that use the applied potential as the reference potential of the respective voltage comparison ICs 9 and 12, and are connected in common. . The potential is given by dividing the DC voltage applied between the terminals and the terminals by the resistance ratio of the resistor 10 and the resistor 11, and is given as the (2) point potential.

The + side input terminal of the voltage comparison IC 15 divides the DC voltage applied between the terminals and the voltage by the resistance ratio of the resistor 19 and the resistor 20 to obtain a (g) point potential, and the voltage comparison IC 15 It is used as the reference voltage.

The resistor 16 is set to the reference voltage in response to the output terminal of the voltage comparison IC 15 turning ON and OFF.
(g) It has the effect of changing the point potential and giving hysteresis to the operation of the voltage comparison IC 15.

Further, the resistor 13 and the resistor 14 have the function of stabilizing the output potentials from the output terminals of the voltage comparison IC 12 and the voltage comparison IC 15, respectively.

NOR gate to form the first logic circuit
For forming IC17 and second logic circuit
Each NOR gate IC 18 is a voltage comparison IC.
6. This is for determining the output conditions of the voltage comparison IC 9, voltage comparison IC 12, and voltage comparison IC 15 by logically combining them. NOR gate IC1
The output of 8 is connected to transistor 2 through resistor 24.
It is output to the base of 5.

The solid-state relay 26 drives a heater 27, which is an output heating section, to be turned on and off in accordance with the ON-OFF conditions of the transistor 25 connected to the input side of the solid-state relay 26. One end of the input side of the solid state relay 26 is connected to a terminal of a DC power supply, and the other end of the input side is connected to the collector of the transistor 25. Further, one end of the output side of the solid state relay 26 is connected to a terminal, and the other end of the output side is connected to the terminal via a heater 27. As a result, an alternating current voltage is applied to the solid state relay 26.

Next, NOR gate IC17 and NOR gate IC1
The output of the NOR gate IC17 and the NOR gate IC18 and the energization conditions for the heater 27 according to the conditions of the point potential (c), the point potential (f), the point potential (li), and the point potential (e) that are input to 8. explain. First, when either or both of the point potential (C) and the point potential (F) are at a high level, the output of the NOR gate IC17 becomes a low level and is input to the NOR gate IC18. When the potential at point (i) and potential at point (e) are both low level, the NOR gate IC 18 outputs a high level and turns on the transistor 25 through the resistor 24.
let As a result, solid state relay 26
is driven, and the heater 27 is energized.

When both the point potential (c) and the point potential (f) become low level, the output potential of the NOR gate IC17 is (re)
The point potential becomes high level and NOR gate IC18
The output becomes low level L. As a result, transistor 25 is turned off, and solid state relay 26 is also turned off. With this, heater 2
7 is cut off.

Next, the operation of this temperature control circuit will be explained.

When the water temperature near the heat-sensitive part of the negative-characteristic thermistor 1, which serves as the first temperature sensor that detects the temperature of water supplied from the water inlet, is low, the resistance value of the negative-characteristic thermistor 1 increases, and (a) the point potential becomes (b). ) is lower than the potential.
As a result, the potential at point (c), which is the output of the voltage comparison IC 6, becomes high level, and the heater 27 is energized via the solid state relay 26. At the same time, the temperature of the hot water near the heat-sensitive part of the negative characteristic thermistor 1 increases, and the resistance value of the thermistor decreases, so that the potential at point (a) becomes higher than the potential at (b), and the potential at point (c) becomes higher. becomes low level.

Furthermore, when the temperature of the hot water near the heat-sensitive part of the negative temperature thermistor 21, which serves as a second temperature sensor that detects a substantially average temperature, becomes low, the negative temperature thermistor 2
The resistance value of 1 increases. And (H) point potential is (G)
Since it is lower than the point potential, the output (F) point potential of the voltage comparison IC 15 becomes a high level, and the heater 27 is energized via the solid state relay 26. As a result, the temperature of the hot water near the heat-sensitive portion of the negative characteristic thermistor 21 increases, and the low resistance value of the negative characteristic thermistor 21 decreases. As a result, (ch)
The point potential becomes higher than the (g) point potential, and the (f) point potential becomes low level.

When either the point potential (c) or the point potential (f) is at a high level, the heater 27 is energized via the solid state relay 26, and when both are at a low level, the energization is cut off. .

The voltage comparison IC 9 and the voltage comparison IC 12 are used for detecting an open failure of the negative characteristic thermistor 1 and the negative characteristic thermistor 21, respectively.
The (d) point potential of the reference potential input terminal of each voltage comparison IC 9, 12 is the (b) point potential which is the reference potential of the voltage comparison IC 6, and the (g) point potential which is the reference potential of the voltage comparison IC 15. It is set to a much lower potential than the potential. Therefore, in normal temperature control, the potential at point (d) is lower than the potential at point (a) and point (h), so the output of voltage comparison IC 9 is at a high level, and the output of voltage comparison IC 12 is at a high level. is at a low level.

When the thermistor is normal, the heater 27 is turned on and off depending on the conditions of the high level and low level of the potential at point (C) and potential at point (f).

Negative characteristic thermistor 1 as a first temperature sensor
When there is an open failure, the resistance value of the negative characteristic thermistor 1 becomes infinite, and the potential at point (a) becomes lower than the potential at point (d). Since the voltage comparison IC 9 compares the potential at point (a) and the potential at point (d), when the potential at point (a) becomes lower than the potential at point (d), the output voltage of this voltage comparison IC 9 changes from high level to low level. On the other hand, the output of voltage comparison IC6 and the voltage comparison
The output of IC9 is connected to the wired
Since it forms an "OR" logic circuit, when at least one of the output of the voltage comparison IC 6 and the voltage comparison IC 9 becomes low level, the potential at point (C) becomes low level. In this way, as mentioned above, (a) point potential is (d)
When the voltage becomes lower than the point potential and the output voltage of voltage comparison IC9 becomes low level, the voltage of the other voltage comparison IC9 becomes low level.
Whether the output of IC6 is low level or high level, the potential at point (C) becomes low level. Therefore, the output of the NOR gate IC 17 operates only under the condition of the (f) point potential, that is, only under the temperature condition of the hot water near the heat sensitive part of the negative characteristic thermistor 21 as the second temperature sensor.

Further, when the negative characteristic thermistor 21 as the second temperature sensor has an open failure, the resistance value of the negative characteristic thermistor 21 becomes infinite, and the potential at point (H) becomes lower than the potential at point (d). Therefore, for voltage comparison
The output (e) point potential of IC12 becomes high level, and (ri)
Regardless of the point potential, the output of the NOR gate IC18 becomes a low level, and the transistor 25 is turned off. In response, solid state relay 26
is also turned off, and power supply to the heater 27 is cut off.

In addition, the explanation about the above temperature control circuit is as follows.
Although based on the electrical circuitry shown, it will be appreciated that similar functionality could be implemented in microcomputer software.

〔Effect of the invention〕

Since the present invention is a temperature control circuit configured as described above, hot water is controlled by two temperature sensors during normal times, and water is always spouted at a predetermined temperature during continuous washing for a long time. . Furthermore, even if the first temperature sensor should fail, the second temperature sensor will control the water temperature in the hot water storage tank to a substantially appropriate temperature. On the other hand, when the second temperature sensor fails, the heater, which is the heating section, is turned off for safety. Therefore, the function as a sanitary cleaning device is greatly improved, and its practical effects are great.

[Brief explanation of drawings]

The figure is a temperature control circuit diagram of the feed water heater in the sanitary washing device of the present invention. 1: Negative characteristic thermistor (first temperature sensor),
21: Negative characteristic thermistor (second temperature sensor),
6: Voltage comparison IC (first temperature comparator), 15:
Voltage comparison IC (second temperature comparator), 9: Voltage comparison IC (first failure detector), 12: Voltage comparison
IC (second fault detector), 17: NOR gate IC
(first logic circuit), 18: NOR gate IC (second logic circuit), 27: heater (heating section).

Claims (1)

[Scope of Claims] 1. A first temperature sensor is disposed near the water inlet at the bottom of the hot water storage tank, a second temperature sensor is disposed near the water outlet at the top of the hot water storage tank, and the first temperature sensor A temperature control command corresponding to the temperature of water entering the hot water storage tank detected by the second temperature sensor is given to the heating unit provided in the hot water storage tank, and the approximately average temperature in the hot water storage tank detected by the second temperature sensor is controlled. In the sanitary cleaning device, the sanitary cleaning device is equipped with a temperature control unit that gives a corresponding temperature control command to the heating unit, and the first temperature sensor and the second temperature sensor are each provided with means for detecting a failure in an open state. When the temperature sensor fails, the second
Sanitary cleaning characterized in that the temperature control section is provided with a means for controlling the temperature of the heating section based on the output of the second temperature sensor and stopping power supply to the heating section when the second temperature sensor fails. Temperature control circuit for the equipment's feed water heater.